Chrysler RAM TRUCK 2500 1994 Service Manual page 267

7 - 12 COOLING SYSTEM
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COOLING SYSTEM DIAGNOSIS—DIESEL—CONTINUED
CONDITION A N D CHECKS
D I A G N O S I S
(5) Test coolant freeze point.
(5)
a—Adjust coolant solution to 5 0 / 5 0 mixture of anti­
(5) Test coolant freeze point.
(5)
f r e e z e a n d water. Refer to Coolant in this group,
b—If a reading is not recorded or below - 5 0 ,
the mixture is too rich. Clean system a n d fill
with a 5 0 / 5 0 mixture of anti-freeze a n d water.
Refer to Coolant in this group.
(6) Ensure proper coolant flow.
(6) a — W i t h the thermostat open and a slight amount of
(6) Ensure proper coolant flow.
(6)
coolant removed, inspect for coolant flow through
the radiator at the filler neck opening,
b—Determine reason for lack of coolant flow a n d repair
a s necessary.
(7) Other possible causes.
(7)
a —If symptom occurs during high speed operation
inspect for plugged air inlet side of the radiator
or condenser, plugged radiator core tubes, a d d - o n
A / C p a c k a g e without proper radiator, engine not
operating within specifications, d r a g g i n g b r a k e s ,
trailer towing or hill climbing, or an insect screen.
b — If symptom occurs during high or low s p e e d
operation inspect for: thermostat being stuck
partially open if ambient temperature is below 7 0 ° F
a n d the vehicle has high mileage, p l u g g e d a i r inlet
side of the radiator or condenser, add on A / C with
incorrect radiator. .
c — If symptom occurs during low speed operation only,
inspect the thermal viscous fan drive. Repair a s '
necessary.
TEMPERATURE GAUGE READS HOT. PRESSURE
CAP VENTS RESULTING IN STEAM A N D COOLANT
TRANSFER TO COOLANT RESERVE TANK:
(1)
Coolant level low in radiator and coolant reserve tank.
(1)
a — F i l l cooling system and vent trapped air.
b —Inspect for leaks. Repair as necessary.
c — Ensure that pressure cap is completely shut a n d s e a l s .
d —If level is low in radiator but normal in th© coolant
reserve tank, check the filler cap-to-coolant reserve
bottle connection and pressure cap seal.
(2) Test coolant freeze point.
(2) Adjust coolant to 5 0 / 5 0 mix of anti-freeze a n d water.
(2) Test coolant freeze point.
(2)
Refer to Coolant section in this group.
(3) Ensure coolant is flowing through system.
(3)
a — With the coolant level low and the thermostat open, Ensure coolant is flowing through system.
(3)
check for coolant flow through the radiator at the
filler neck.
b — If a metal cracking sound is heard, inspect for core
sand restricting coolant flow through the water
jacket and/or a faulty cylinder head casting.
(4)
Thermostat stuck in the closed position (prevalent in
(4)
Replace thermostat if found to be stuck in closed
cold ambient temperatures).
(4)
position. Refer to the Thermostat Testing section in
this group.
(5) Cylinder head gasket leak.
(5)
Inspect for leaking cylinder head gasket with a Cylinder head gasket leak.
commercially available Block Leak Tester.
J9407-4
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